> -----Original Message----- > From: platform-driver-x86-owner@xxxxxxxxxxxxxxx [mailto:platform-driver-x86- > owner@xxxxxxxxxxxxxxx] On Behalf Of David Zarzycki > Sent: Tuesday, April 17, 2018 11:16 AM > To: platform-driver-x86@xxxxxxxxxxxxxxx > Subject: Dell Precision 7920 fan problems > > Hello, > > As a preface, my config: > Dell Precision 7920 with two CPUs and the 1.4.1 BIOS. > Red Hat Fedora 28 with their v4.16.1 kernel. 7920 Tower or rack? They're helpfully both called 7920. > > I’m finding that the second CPU isn’t thermally managed. It seems to send about > 1000 thermal distress interrupts/core/package/second under load and the second > CPU throttles itself down to 1.7 GHz. If I force the fans to full speed via /sys, then > the clock speed runs as expected (about 3.2 GHz). > Which interface exactly are you using to increase fan speed? Assuming your platform supports it, I would recommend that you keep --fan-speed configured to "auto" in DCC/CCTK or in BIOS setup. Details on this option are here: http://www.dell.com/support/manuals/us/en/19/command-configure-v3.3/dellcommandconfigure-cli-3.3/--fanspeed?guid=guid-8ec8603a-3691-48ac-ae70-f42d76eaa97c&lang=en-us I'm sorry I don't know off hand if your system should support it. > Who is to blame here? Linux? Or the Dell BIOS? If the BIOS is to blame, how does > one file bug reports against Dell? It's worth initially checking with 4.17-rc1. There are some fixes in ACPI around MLC code that have resolved bugs that manifest in peculiar ways. Assuming that doesn't help I would doubt this particular mailing list (platform-x86) is the right home for discussing it. I would recommend to file a kernel bug against ACPI to start. If the ACPI experts conclude that there is likely a BIOS bug at play you can contact Dell ProSupport to report it and they can bring it to the right people to look at in Dell.
